Computer Networks

A bridge is an layer 2 device - it works based on mac address. bridge is s/w based.It is usually used to bridge 2 networks (or even more in recent times)Bridge is configured by having the the mac address of the switches connected directly to it.

Hi,Classless intrnet domain routing (CIDR) , if default routing this is very useful where we don't need to very much about what is the subnetting about that class of ip's.shridhar

It is very important model for networking:

The main aim to design the OSI model is that actully they want to set a standerd for the communication and want to standarized the network equipement so that they would not be any Brand consuines

RIP is one of the most enduring of all routing protocols. RIP is also one of the more easily confused protocols because a variety of RIP-like routing protocols proliferated, some of which even used the same name! RIP and the myriad RIP-like protocols were based on the same set of algorithms that use distance vectors to mathematically compare routes to identify the best path to any given destination address.

The Network Time Protocol (NTP) is a protocol for synchronising the clocks of computer systems over packet-switched, variable-latency data networks. NTP uses UDP as its transport layer. It is designed particularly to resist the effects of variable latency.

In topology and related areas of mathematics, a subnet is a generalization of the concept of subsequence to the case of nets. The definition is not completely straightforward, but is designed to allow as many theorems about subsequences to generalize to nets.A portion of a network that shares a common address component. On TCP/IP networks, subnets are defined as all devices whose IP addresses have the same prefix. For example, all devices with IP addresses that start with 100.100.100. would be part of the same subnet.

Emergency Repair Disk, an ERD is a diskette that creates backups of important system files and settings and is used to help troubleshootand fix issues for Microsoft WINNT and WIN 2000. The ERD is used in conjunction with the Windows repair option and you will be prompted for the diskette when needed. Note: The ERD is not to be confused with a standard boot diskette as it cannot be used alone. The ERD is capable of performing such checks as:1. Verifying the boot sector is not corrupt. 2. Repairing any startup files. 3. Locate any missing or damaged system files.

BGP stands for Border Gateway Protocol. It is an inter-AS ( Autonomous System Routing Protocol ). BGP is the routing protocol that runs the Internet. BGP is used to interconnect network islands ( ASs ) together. BGP is the only IP routing protocol that runs on TCP instead of IP like the other routing protocols, OSPF, RIP, EIGRP.Also BGP is also known as a path vector protocol as it not only tells you how to get to a network IP prefix, but it shows you an AS path of the reachable network.There are two versions of the BGP protocol. EBGP ( External Border Gateway Protocol ) and IBGP ( Internal Border Gateway Protocol ).

The data unit created at the application layer is called a message, at the transport layer the data unit created is called either a segment or an user datagram, at the network layer the data unit created is called the datagram, at the data link layer the datagram is encapsulated in to a frame and finally transmitted as signals along the transmission media.

Osi reference model consisting of 7 layers hepls the data to be moved in more optimal from source to the destination.And here the protocols are better hidden so the furhter enhancement can be done easily.This reference model can be used for both connection oriented and connectionless service.

Every line has an upper limit and a lower limit on the frequency of signals it can carry. This limited range is called the bandwidth.

The HELLO protocol uses time instead of distance to determine optimal routing. It is an alternative to the Routing Information Protocol.

Session Announcement Protocol, a computer protocol for broadcasting multicast session information Service Advertising Protocol, an IPX network protocol that makes the process of adding and removing services on an IPX internetwork dynamic Service Access Point, an identifying label for network endpoints used in OSI networking

VLAN also refers to a LAN port grouping within a single switch. VLANs improve security by isolating groups. A VLAN is a bridging domain and all broadcast and multicast traffic is contained within it.

FramesPacket data unit(PDU)is called----------------segment at transport layerpacket at a network layerframe at data link andbit/bytes at physical layer

it is used in cryptography, a key distribution center (KDC) is part of a cryptosystem intended to reduce the risks inherent in exchanging keys.

The Trivial File Transfer Protocol (TFTP) allows a local host to obtain files from a remote host but does not provide reliability or security. It uses the fundamental packet delivery services offered by UDP.The File Transfer Protocol (FTP) is the standard mechanism provided by TCP / IP for copying a file from one host to another. It uses the services offered by TCP and so is reliable and secure. It establishes two connections (virtual circuits) between the hosts, one for data transfer and another for control information.

PING stands Packet Internet Gopher. This is a utility for ensuring connectivity between computers . ICMP protocol works behind this utility. Under it , sending node sends packets to destination node and reply is received if there is proper communication between two.

There are three possible ways of data exchange. These are:1. Simplex: in this, data is transmitted in one direction only. this means one end will always be a transmitter and the other end will always be a reciever.2. Half-Duplex: in this, data is permitted to flow in either direction, but not silmultaneously. At a given time, the transmission can take place only in one direction.3. Full-duplex: A transmission system in which data can be transmitted in both directions simultaneously.